Living in a new home without moving out: for most people this is only a dream, but this will become a reality for the 64 families living via Passeggiata dei Castani in Bolzano. Following a successful renovation process carried out in the framework of the Sinfonia Smart City Initiative, the 7.100 square meters social housing building is now putting an end to its dependence on fossil fuels. From now on, most of the energy consumed in the building will be produced mostly on site, using renewable energy from the sun and the ground.
Pre-fabricated façades: a tenant-friendly insulation strategy
In July 2017, renovation activities were starting in the buildings with the objective of reaching zero-energy standards through the implementation of energy efficiency measures complemented by the installation of local renewable energy production systems. One year after, partners achieved the hardest part of the work and it is already time for the finishing touches.
As a first step to improve the buildings’ energy efficiency, the design team of Passeggiata dei Castanihas created a tailor-made pre-fabricaded façade made of wood beams and agglomerated wood panels, to be installed directly on the existing façade. The pre-fabricaded façade was tested for the first time in the laboratory of Sinfonia partner Eurac and the prototype was made in the company's laboratory. This solution made it possible to add easily a new insulation layer to the building and minimised the disturbances for tenants, allowing them to stay home during the renovations. To further increase the building’s energy efficiency, windows were also replaced, and a new mechanical ventilation system was installed. Once the renovations fully completed, the building is expected to consume almost four times less energy than before.
Renewable energy for low-income families
On the total amount of energy needed in the newly refurbished building, over 75% should come from local renewables sources. And this energy will be produced directly on-site, through a solar thermal plant and a 20kWp field of solar panels installed on the roof, as well as a geothermal heating system pumping energy from the ground. In the mountainous site of Bolzano, this is the first time that geothermal energy is exploited for residential housing. With this new system, the energy is piped from the ground through 15 probes located at 150 meters below the surface. On site, the implementation was a real success: even though the probes had to be installed deeper in the ground than planned due to a deviation between earth layers, this solution should cover more than 70% of the heating needs of inhabitants. For the tenants - mostly low-income families, including one quarter of retired people, the use of renewable energy sources produced directly in the building will represent a real cost-saver on their energy bills.
Further to the technical achievements, the Bolzano municipality, owner of the building, has made its motto to engage tenants throughout the whole renovation process. “Establishing a climate of trust and providing tenants with clear and transparent information in due time is key to be able to solve problems on a daily basis in cooperation with tenants and safeguard the success of the refurbishment projects” says Rosita Izzo, Project Manager at the Municipality of Bolzano. To achieve this objective, various activities have been set up to engage the building’s occupants from the beginning of the process. This included the organisation of regular meetings, the distribution of user manuals, as well as the invitation to visit demo apartments for inhabitants to get to know the new devices and better realise the benefits from the refurbishment. As from February 2019, the works will be finalised in via Passeggiata dei Castani, letting it to the tenants to share their experience with their neighbours and thus facilitate local replication of energy efficient solutions.